Dave Lauer, former trader at HFT firm Allston trading, recounts what it was like to work during the 2010 flash crash, when the Dow crashed 1000 points only to recover immediately.

There was nothing. There was no market for moments, for seconds there was no market. And we're just all sitting there and you're staring into oblivion and you have no idea what is about to happen, but something you that could not possibly have thought could happen just happened. And you're looking at the market, and it's not there.

Lauer says he left high-frequency trading a year later, unhappy that many of the country's greatest minds work to extract pennies from the HFT system instead of helping humanity.

"Looking back on that day, I lost faith in capitalism or at least what we had built to be capitalism," he says. "I didn't trust it anymore."